maint: Clean up m-files to follow Octave coding conventions. Try to trim long lines to < 80 chars. Use '##' for single line comments. Use '(...)' around tests for if/elseif/switch/while. Abut cell indexing operator '{' next to variable. Abut array indexing operator '(' next to variable. Use space between negation operator '!' and following expression. Use two newlines between endfunction and start of %!test or %!demo code. Remove unnecessary parens grouping between short-circuit operators. Remove stray extra spaces (typos) between variables and assignment operators. Remove stray extra spaces from ends of lines.

--- a/scripts/geometry/voronoin.m
+++ b/scripts/geometry/voronoin.m
@@ -75,7 +75,7 @@
 endfunction
 
 
-%% FIXME: Need functional tests
+## FIXME: Need functional tests
 
 %!error voronoin ()
 %!error voronoin (1,2,3)